Transmission gasket replacement

[Kim K Kaiser]

After finding leak arpund rim of trans pan.  I ordered a gasket.  

I was checking to see if there are any pitfalls or suggestions to getting it right.

I assume drain pan from the drain bolt, then pull the pan and replace.  Will anything drop or fall from the underside of the pan on removal that i should be concerned with.

[Kim K Kaiser]

Well, i pounded out the bolt holes all thecway around, used a strait edge to ck flat.  Took greatvcare to rebolt at 7 then 11 pounds,  notvwanting to split another gasket, left itvat 11.  Filled and started engine,  ran a while, shut off, waited went bk to chk.  Leaking along passenger side.  Justva thin smooth layer of fluid justvbelow gasketv on lip. Other side,  bck n frnt were dry.

So, i tighrened up to the 13 lbs as noted in book.  Statred, waited, wentvto ck.  Same result. Thin layer along rim below gasket.

Now thevpan has been put back to smooth per the strait edge.  

Am i missing a step somewhere?  

[Jason Edge]

Did you clean the bolt threads on bolts and tapped threaded holes? You should be able to freely screws each bolt all the way in with your fingers with the pan removed. If bolt holes are filled with gunk the pan will never snug up to the transmission. Also make sure each mating surface is completely clean. Other than that I would lay the pan on a perfectly flat surface, turn off the lights, and use a flash light to go around the edges and look under and check for flatness of pan. 

[Kim K Kaiser]

i cleaned the bolts etc and was able to use fingers to get them flush, before using,, i will pull it again, chk for flat on that side,, something must be off.. i am glad i bought two, figuring on a misstep,, 

[3ft7bqmb7dryo]

Did you put the black rtv on both sides of the gasket? will need to get a new gasket, as the old one has already been crushed into place.

[Kim K Kaiser]

no,, i did not, i seem to have read over at the cad & lasalle forum somewhere that the rtv could come loose, and get into the transmission.  I thought of that but after reading that I decided to leave it off.. 

so, using the rtv is acceptable?

[Jason Edge]

I've never used any rtv sealant on the transmission pan gasket. Why are you using RTV sealant?  Sealing the mating surfaces is the purpose of the gasket? I rarely use this stuff and never on 2 flat surfaces unless specifically indicated in the shop manual. As long as surfaces are clean and flat and screws threads are clean and true you should not need this messy stuff for attaching 2 flat surfaces.

[Kim K Kaiser]

i did not use it on this job.   i had read it was a potential problem if a piece of it came loose or dislodged and got into the system, that was enough to scare me away from it,, 

i will work on it again to day, weather permitting,,,go back over all the info and make sure i didnt leave out a step..

[Tosh Dickenson]

Hi Kim,

I think you may be overthinking it, this is a pretty straightforward operation.  You are probably doing everything correctly but are dealing with a warped pan or substandard gasket.

The edges of the pan may be straight but the whole pan could be warped.  Set the pan bolt flange down on a flat surface and see if it rocks.  If it does, try coaxing it back into shape with your hands.

If the pan is relatively flat, I would look for a higher quality gasket, preferably cork.  You may have to go to an actual transmission shop or possibly the GM dealer may find one for you.  

I suspect you have a very thin gasket.  You are probably torquing correctly but the gasket isn't thick enough to fill the voids between the bolt holes.

There is RTV sealant that is appropriate for use with transmission components.  I generally use a spray tack adhesive just to hold the gasket to the pan for installation.

Final thought:  Are you sure the filter is pushed all the way up into the transmission and is not interfering with pan fit?

[Kim K Kaiser]

Yhanks,  well, i hv a fel pro gaske .  Its a black looks like cork appearance,  i did use a light adhesive to get it to stick.   I will ck the pan again

Thanks

[David Thomas]

Kim, you probably have the pan well sealed. Look a little higher and you will probably find that your leak is from the dipstick tube O'ring seal. This is a common leak source. Clean and dry the area around the tube where it enters the transmission.  The tube must be square and straight to the case opening. After cleaning all oil off, dust some baby powder around the area where the oil is apearing, you'll be able to find the leak when it soaks the powder.

Another leak source is the oil cooler lines. There are two hoses connecting the spigots out of the transmission to the lines running to the radiator. Those sometimes do leak and can look like the pan is leaking when the oil runs down the transmission case.

Your description of the leak comming off the right front corner points more to the dipstick tube as the leak source.  HTH

[Kim K Kaiser]

Hi David,  yep, i already thoufht of that,  seema dry there.

Secondly,  after tapping and measuring for two hours, third gasket split at 10 lbs,    i know it was flat,  it was not warped,   thanfully i didnt load up anoth 35 doallrs of trans oi .  Wits, end,    gonna give it a rest for a day or so.

For reference,  used fel pro gaske .  Its a black oily looking dasket.   Im guessing cork, but has a black look.

[Kim K Kaiser]

Sounds like a plan.  Will give it a go.  Put straitedge on case and see if its flat 

Thanks